_f_, Long head of triceps; _f′_, external head of triceps; _g_,
anterior superficial pectoral; _h_, posterior deep pectoral; _h′_,
anterior deep pectoral; _i_, serratus thoracis; _i′_, serratus
cervicis; _l_, obliquus abdominis externus, and _l′_, its
aponeurosis, the posterior part of which has been removed; _m_,
serratus posticus; _p_, gluteus medius; _r_, semitendinosus; _s_,
sacro-coccygeus superior; _t_, sacro-coccygeus lateralis; _u_,
coccygeus; _v′_, biceps brachii; _x_, rhomboideus; _y_, _y′_,
trachelo-mastoideus; _z_, supraspinatus; _z′_, infraspinatus; _1_,
cartilage of scapula; _2_, spine of scapula; _5_, external
tuberosity of humerus; _6_, deltoid tuberosity; _8_, olecranon;
_16_, external angle of ilium; _19_, trochanter major; _20_,
patella; _21′_, external condyle of tibia; _26_, articular processes
of cervical vertebræ; _27_, parotido-auricularis; _28_, vastus
externus; _28′_, rectus femoris; _28″_, trochanter tertius; _29_,
semimembranosus; _30_, gastrocnemius; _31_, sacro-sciatic ligament;
_32_, omo-hyoideus; _33_, complexus; _34_, rectus capitis anterior
major; _35_, spinalis dorsi; _36_, longissimus dorsi; _37_,
transversalis costarum; _38_, teres minor; _39_, brachialis; _40_,
external intercostal; _41_, obliquus abdominis internus; _42_,
iliacus; _43_, transversus abdominis. (After Ellenberger-Baum, Anat.
für Künstler.)
]
_Action._—Acting together, to extend the neck; acting singly, to flex
and rotate the neck to the opposite side.
_Structure._—The muscle is composed of two sets of bundles. The
superficial bundles are directed obliquely forward and inward, each
passing from an articular process to the spine of the preceding
vertebra. The deep bundles are shorter and run straight from an
articular process to that of the preceding vertebra.
_Relations._—Superficially, the complexus, longissimus,
trachelo-mastoideus, and great oblique muscles; deeply, the spinalis
muscle, the ligamentum nuchæ, and the arches of the vertebræ.
_Blood-supply._—Deep cervical and vertebral arteries.
_Nerve-supply._—Dorsal branches of the last six cervical nerves.